Impact of mıcrowave treatment’s locatıon on flotabılıty of chalcopyrıte and pyrıt: a case study of Sarcheshmeh copper complex ore

This work aims to investigate the effect of microwave-assisted flotation on chalcopyrite and pyrite’s floatabilities in a porphyry copper complex ore by varying microwave’s local position before crushing (BC), after crushing (AC) and after milling (AM). Indivuduals given samples for each state were pre-treated with a variable power microwave at power levels of 90, 180, 360, 600, and 900W for 15, 30, and 60s. Furthermore, 45 rougher floatation experiments were carried out using a laboratory mechanical Denver flotation cell on both microwave-treated and untreated samples. Particle surface properties were characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. It was found that chalcopyrite and pyrite’s floatabilities monotonically increased by increasing the exposure time and power level for uncrushed preconditioned samples owing to an enhancement on mineral liberation degrees together with the formation of sulphide species and polysulphides on the mineral surfaces. However, flotation results of treated samples for crushed one (AC) revealed an optimum range where chalcopyrite and pyrite’s recoveries improved by increasing power level and exposure time to 30s while thereafter dropped down significantly. Finally, the formation of intensive oxide layers on mineral surfaces of milled samples led to a substantial reduction in the recoveries by increasing the power level and exposure time for AM-sample. Finaly, it was concluded that microwave’s local position at BC induced the best separation efficiencies in flotation section compared to the untreated and microwave-treated samples (crushed and milled).